This invention relates generally to keyless entry systems and, in particular, to a vehicle-mounted transmitter that uses remote transmitter codes to unlock doors or perform other functions in response to an operator input.
Many higher-end cars and trucks now come equipped with keyless entry systems. These typically take the form of a pocket-sized fob with several pushbuttons that unlock doors and perform other functions through encoded RF signals transmitted to a vehicle-installed receiver. Depending upon the sophistication of the system, keys may be provided to activate and deactivate alarms, turn lights on or off, and even start the car on cold days. Though convenient, keyless entry systems of the type just described are also expensive, costing several hundred dollars, even if factory installed.
Certain types of vehicles, luxury cars in particular, also come equipped with door-mounted keyless entry systems. These typically take the form of a keypad strip positioned close to the door handle, enabling an authorized user of the vehicle to punch in a numeric code and gain entry to the vehicle. These keypad strips are generally low in profile for easy maintenance. There are also vehicles equipped with both wireless and door-mounted keyless entry systems, but they are generally unrelated in terms of electronic protocol. That is, the wireless systems transmit RF codes, whereas the door-mounted systems are hard-wired and do not require sophisticated encoding.
The present invention addresses the desire to combine wireless and vehicle-mounted keyless-entry modalities in a cost-effective system configuration. Although there are many patents and other references related to the problem of keyless-entry, none address the problem solved by the instant invention. U.S. Pat. No. 5,467,080 to Stoll et al., for example, discloses a hardwired, keypad-actuated, keyless entry system where the keypad is integrated into the body of the car. This patent resides in the use of a capacitive, touch sensitive keypad, and does not discuss the use of a wireless transmitter.
U.S. Pat. No. 5,252,960 to Duhame discloses a keypad entry transmitter for use with a garage door opener. A wireless transmitter including a keypad is mounted outside of the garage such that when the proper code is entered into the keypad, the transmitter delivers a garage door opening signal to a receiver mounted inside of the garage. This patent fails to disclose a vehicle mounted keypad in general, or the use of keys operable through glass, in particular.
U.S. Pat. No. 5,077,831 to Weber discloses a wireless transmitter which requires the code to be input before the transmitter becomes active. This patent fails to disclose a vehicle mounted transmitter or any details of the code input portion.
The present invention resides in a remote-control transmitter including means for entering an identification code so that only an authorized operator can use the device. The identification code may be entered through one or more of the same keys used to operate the transmitter, or means specific to operator authorization may be provided.
The use of an identification code allows the authorized operator to be less concerned that the inventive remote-control transmitter will be discovered or tested by an unauthorized user. As such, the transmitter may be mounted directly on a vehicle, for example, in much the same manner as existing hard-wired keyless entry systems, but without the need for any vehicle modification. Such an application enables the owner of a vehicle equipped with a receiver of remote-control codes to have an additional, keypad-operated transmitter to perform some or all of the same functions as those available through the use of an existing wireless transmitter. The inventive system may be provided as a factory-, dealer-, after-market or owner-installed option, and use of the additional transmitter does not preclude the use of the existing remote.
In a preferred embodiment, the inventive transmitter is located within the interior of a vehicle, with the keypad being installed either inside or outside of the vehicle, depending upon the desired configuration.
To implement an external keypad, the keypad may be mounted proximate to the top edge of a side window, and communicate with the transmitter and other electronics within the vehicle through a flexible connector draped over the top edge of the window. In a preferred, entirely internal embodiment, the switch panel is mounted behind a small section of the vehicle""s window glass, in a lower corner of the windshield, for example, with electrical, magnetic or optical proximity detection being used to sense the operator""s finger or operator movements through the glass.
For use in conjunction with an existing wireless transmitter/receiver, the transmitter provided by the invention preferably uses some or all of the same codes as the existing remote transmitter to perform a desired function such as door or trunk unlocking, light activation, and so forth.
The inventive transmitter is preferably battery-operated, thereby obviating the need for extraneous wiring to the device. To conserve battery power, the system automatically powers down during periods of non-use, with the entry of an appropriate stimulus being used to initiate operational modes requiring increased power consumption. In one embodiment, entry of the authorization code may be used as a wake-up signal such that for a short period of timexe2x80x94a few seconds, for examplexe2x80x94depression of the appropriate buttons will initiate a desired function. In another embodiment, a sensor is used to detect a sound or a vibration such as tapping on the glass of the vehicle which, in turn, functions as a wake-up signal. To further prevent false activation, the tapping or other input associated with the wake-up may, itself, be programmably encoded.